This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The Flow Cytometry Core Laboratory instrumentation includes 2 Becton-Dickinson (BD) FACSCaliburs, a BD LSRII and a BD FACSAria. The FACSCaliburs are capable of 6 parameter analysis (4 colors plus forward and side scatter). They are used for 4-color acquisitions, cell proliferation studies using carboxy-fluorescein diacetate succinimidyl ester (CFSE) and cell ploidy determinations. Both the LSRII and the FACSAria are used for multiparameter sample determinations. Each is a digital platform containing 3 lasers and capable of 14 parameter analysis (12 colors plus forward and side scatter). The FACSAria is also a high speed cell sorter, capable of aseptically sorting up to 4 subpopulations simultaneously with exceptional purity. The needs of individual investigators varied. Some investigators utilized the comprehensive services offered by the core lab: from monoclonal antibody selection through data acquisition. The majority of investigators processed their own samples in preparation for flow cytometry acquisition. The core lab provides limited data analysis;most investigators perform their own data analysis. Raw data files are distributed to the various investigators via a secure Tulane National Primate Research Center server. Flow Cytometry Laboratory provided services with 4 types of analyses. Service totals for 2009 are as follows: Calibur = 2840;Multicolor = 14859;Sort = 41 and TruCount = 1820. These services were provided to both core and affiliate investigators. The AIDS research program is the largest user of the Core.